The present invention relates to a very low cost portable compact scanner. More particularly it is directed to a detachable portable platen accessory for use with a portable compact scanner copier which will enable copying from books and magazines.
Historically, copies of original documents have been produced by a xerographic process wherein the original document to be copied is placed on a transparent platen, either by hand or automatically through the use of a document handler, and the original document illuminated by a relatively high intensity light. Image rays reflected from the illuminated document are focused by a suitable optical system onto a previously charged photoconductor, the image light rays functioning to discharge the photoconductor in accordance with the image content of the original to produce an electrostatic latent image of the original on the photoconductor. The electrostatic latent image so produced is thereafter developed by a suitable developer material commonly referred to as toner, and the developed image transferred to a sheet of copy paper brought forward by a suitable feeder. The transferred image is thereafter fixed to the copy paper by fusing to provide a permanent copy while the photoconductor is cleaned of residual developer preparatory to recharging. More recently, interest has arisen in electronic imaging where, in contrast to the aforedescribed xerographic system, the image of the document original is converted to electrical signals or pixels and these signals, which may be processed, transmitted over long distances, and/or stored, are used to produce one or more copies. In such an electronic imaging system, rather than focusing the light image onto a photoreceptor for purposes of discharging a charged surface prior to xerographic development, the optical system focuses the image rays reflected from the document original onto the image reading array which serves to convert the image rays to electrical signals. These signals are used to create an image by some means such as operating a laser beam to discharge a xerographic photoreceptor, or by operating some direct marking system such as an ink jet or thermal transfer printing system.
It is generally advantageous if the normally separate document reading and copy printing operations could be combined. If some of these reading/writing functions could be combined, system operation and synchronization could be simplified and system cost reduced through the use of fewer parts.
There are systems in the prior art that address the above identified concerns. For example:
U.S. Pat. No. 4,496,984 to Stoffel and U.S. Pat. No. 4,583,126, a division of the above-identified reference, disclose an input/output scanner for simultaneously reading a document and writing a copy. The document and copy sheet are fed in back to back relation to the read/write station. A monolithic full width reading array reads each line in two steps, to improve resolution. The writing array consists of rows of ink jet nozzles, of which the number and disposition is in direct correspondence to the sensors of the read bar.
U.S. Pat. No. 4,424,524 to Daniele discloses a full width read/write LED array for scanning a document in the read mode or exposing the photoreceptor in the write mode. A Selfoc optical fiber lens array is used for focusing the full width LED array on the document or photoreceptor.
A difficulty with these prior art systems is the complexity and cost of separate components such as the complex optics, photoreceptor and developer in a typical xerographic process such as the Daniele system. In other systems such as the Stoffel system, it is necessary for an operator to manually combine a document and copy sheet into a single unit for manual insertion to the machine feed rolls. Such a system also has a significant cost penalty associated with components such as the monolithic full width reading array.
The copier concepts described in the last three cross referenced copending applications are attempts to reduce cost and complexity of such a copier while at the same time maximizing compactness and portability. In normal operation of the copier concept described in the last three cross referenced copending applications the top cover is opened the copy paper inserted in the lower slot, the document registered against the tab on the top cover. When the top cover is closed the copying sequence is initiated. The scan head moves across both the document and copy paper simultaneously reading a band of information (about 0.64") from the document and printing it on the copy paper. After each scan the document and copy paper drive rolls make one complete revolution which advances both the document and the copy paper 0.64" in opposite directions. The scan carriage then sweeps across the document and copy paper in the opposite direction to read and print the next band of information. These concepts have the limitation in that they are capable of handling only cut sheet documents. This can put a severe limitation on the range of applicable utilities for this portable copier by the user. Since it is not capable of not making copies from books and magazines on the spot. The present application is directed to a solution to the difficulty and in particular is directed to providing a detachable portable platen for use with a portable copier which will enable the copying from books and magazines.